Toxicoproteomics is the use of global protein expression technologies to gain a better understanding of environmental and genetic factors in stressor exposure and in long term development of disease. The formulation of a strategy to integrate transcript, protein and toxicology data is a major objective for the field of Toxicogenomics. An objective toward this goal was met by publication of a strategy for research in toxicoproteomics by Merrick, 2008. The National Center for Toxicogenomics pursued a strategy of conducting parallel DNA microarray and proteomic analyses on the same tissues from Toxicogenomics studies. The advantage of this approach is to bring more information to bear on toxicological problems in identifying affected, biochemical and regulatory pathways that can lead to biomarker and toxicity signature discovery. Both DNA microarray and proteomic technologies are driven by measuring differential expression of transcripts and proteins after toxicant exposure. The high level of information density and gene discovery potential in microarray analysis can be enhanced by proteomics technologies. An objective toward this goal was met by publication of a compendium transcript signatures of hepatotoxicants by Lobenhofer et al., 2008 and the supporting bioinformatics databases to store and query them in CEBS by Waters et al., 2008. Frozen tissues from liver and serum samples of rats exposed to hepatotoxicant agents have been stored for possible proteomic analysis at some future date.